The Etruscan shrew (Suncus etruscus), also known as the
Etruscan pygmy shrew or the white-toothed pygmy shrew is the smallest known
mammal by mass, weighing only about 1.8 grams (0.063 oz) on average The
bumblebee bat Craseonycteris thonglongyai is regarded as the smallest
mammal by skull size.

The Etruscan shrew has a body length of about 4 centimetres (1.6 in) excluding
the tail. It is characterized by very rapid movements and a fast metabolism,
eating about 1.5–2 times its own body weight per day. It feeds on various small
vertebrates and invertebrates, mostly insects, and can hunt individuals of the
same size as itself. These shrews prefer warm and damp climates and are widely
distributed in the belt between 10° and 30°N latitude stretching from Europe and
North Africa up to Malaysia. They are relatively rare and are endangered in some
countries.

Description

The Etruscan shrew has a slender (not truncated) body, with a length between 3
and 5.2 cm (1.2 and 2.0 in) excluding the tail, which adds another 2.4 to 3.2 cm
(0.94 to 1.3 in). The body mass varies between 1.3 g (0.046 oz) and 2.5 g (0.088
oz)and is usually about 1.8 g (0.063 oz).In comparison, the related Greater
White-toothed Shrew can be twice as long and weighs four to five times more. The
head is relatively large, with a long, mobile proboscis, and the hind limbs are
relatively small. The ears are relatively large and protuberant. The Etruscan
shrew has a very fast heart beating rate, up to 1511 beats/min (25 beats/s) and
a relatively large heart muscle mass, 1.2% of body weight The fur colour on the
back and sides is pale brown, but is light gray on the stomach. The fur becomes
denser and thicker from fall through the winter. The shrew usually has 30 teeth,
but the 4th upper intermediate tooth is very small (rudimentary), and is absent
in some individuals. Near the mouth growth a dense array of short whiskers,
which the shrew actively uses in searching for prey, especially in the night.
Dimorphism in body features between males and females is absent.

Activity

Etruscan shrews live alone, except during mating periods. Their lifespan is
estimated at typically around two years, but with a large uncertainty. They
protect their territories by making chirping noises and signs of aggressiveness.
They tend to groom themselves constantly when not eating, and are always moving
when awake and not hiding. The hiding periods are short, and typically last less
than half an hour. Clicking sounds are heard when these shrews are moving, which
cease when they rest. The shrews are more active during the night when they make
long trips; during the day, they stay near the nest or in a hiding place. They
reach their maximum level of activity at dawn.

The movements of the Etruscan shrew are rapid, with a rate of about 780 min−1
(13 s−1). In cold seasons and during shortages of food, the shrews lower their
body temperatures down to about 12 °C (54 °F) and enter a state of temporary
hibernation to reduce energy consumption. Recovery from this state is
accompanied by shivering with the frequency of about 3500 min−1 (58 s−1).[3]
This induces heating, with the rate up to 0.83 °C/min, which is among the
highest values recorded in mammals; the heart rate increases exponentially with
time from 100 to 800–1200 beats/min, and the respiratory rate rises linearly
from 50 to 600–800 beats/min.

Etruscan shrews mate primarily from March to October, though they can be
pregnant at any time of the year. Pairs usually form in the spring and may
tolerate each other and their young for some time at the nest. The gestation
period is 27-28 days, and they have 2–6 cubs per litter. Cubs are born naked and
blind, weighing only 0.2 g (0.0071 oz). After their eyes open at 14 to 16 days
old, they mature quickly. The mother usually moves the young when they are 9 to
10 days old and if disturbed leads them by caravanning them to a new location.
The young Etruscan shrews are weaned at 20 days old. By three to four weeks of
age, the young are independent and are soon sexual mature.

Distribution

The Etruscan shrew inhabits a belt extending between 10° and 40°N latitude
across Eurasia. In Southern Europe, it has been found in Albania, Bosnia and
Herzegovina, Bulgaria, Croatia, Cyprus, France, Macedonia, Malta, Montenegro,
Greece, Italy, Portugal, Slovenia, Spain, and Turkey, with unconfirmed reports
in Andorra, Gibraltar and Monaco; it has been introduced by humans to some
European islands, such as Canary Islands.

The shrew also occurs in North Africa (Algeria, Egypt, Libya, Morocco, Tunisia)
and around Arabian Peninsula (Bahrain, Israel, Jordan, Lebanon, Oman, Syria, and
Yemen including Socotra). In Asia, it was observed in Afghanistan, Azerbaijan,
Borneo, Bhutan, China (Gengma County only), Burma, Georgia, Guinea, India, Iran,
Iraq, Kazakhstan, Laos, Malaysia (Malaysian part of Borneo island), Nepal,
Pakistan, Philippines, Sri Lanka, Tajikistan, Thailand, Turkey,
Turkmenistan and Vietnam. There are unconfirmed reports of the Etruscan shrew in
West and East Africa (Guinea, Nigeria, Ethiopia) and in Armenia, Brunei,
Indonesia, Kuwait and Uzbekistan. The shrew is relatively rare, especially in
Azerbaijan, Georgia (included into the Red Book), Jordan and Kazakhstan (Red
Book). Even where not endangered, its density is always lower than of the other
shrews living in the area.

Habitat

The Etruscan shrew favours warm and damp habitats covered with shrubs, which it
uses to hide from predators. Areas where open terrain such as grasslands and
scrub meet deciduous forests are usually inhabited. It can be found at sea level
but is usually confined to the foothills and lower belts of mountain ranges,
though has been found up to 3,000 m (9,800 ft) above sea level. It colonizes
riparian thickets along the banks of lakes and rivers, as well as
human-cultivated areas (abandoned gardens, orchards, vineyards, olive groves and
edges of fields). The shrew, however, avoids intensively cultivated areas, as
well as dense forests and sand dunes. It is poorly adapted to digging burrows,
so arranges its nests in various natural shelters, crevices and others
uninhabited burrows. They frequent rocks, boulders, stone walls and ruins,
darting quickly in and out between them.

Hunting and feeding

Because of its high ratio of surface area to body volume, the Etruscan shrew has
an extremely fast metabolism and must eat 1.5–2.0 times its body weight in food
per day. It feeds up to 25 times per day, mostly on various invertebrates
(insects, their larvae, earthworms, etc.), as well as small vertebrates (the
young of frogs, lizards and rodents), and can hunt prey of nearly the same body
size as itself. It prefers species with a soft, thin exoskeleton, so avoids ants
when given a choice. Grasshoppers, where common, are often regular prey. It
kills large prey by a bite to the head and eating it immediately, but takes
small insects back to its nest. When hunting, the Etruscan shrew mostly relies
on its sense of touch rather than vision, and may even run into its food at
night.

Predators and threats

The largest threat to Etruscan shrews originates from human activities,
particularly destruction of their nesting grounds and habitats as a result of
farming. Etruscan shrews are also sensitive to weather changes, such as cold
winters and dry periods. Major predators are birds of prey, especially owls.

Conservation Actions:

This species is present in many protected areas. It is listed
on Appendix III of the Bern Convention